Obtaining access to offshore structures such as wind turbines and oil and gas installations, to undertake, for example, servicing, maintenance or abandonment operations can be extremely hazardous. Often the vessel front which the servicing, maintenance or abandonment operation is to be performed, draws up alongside the offshore structure and the engineer steps or jumps onto the structure or man rides off the vessel to work on the structure. In the case of maintenance of a wind turbine, for example, the maintenance engineer steps or jumps onto a vertical ladder on the wind turbine base. However, if a repair is required to, for example, the wind turbine blades, this often requires a vessel with cranes to be brought into position to lift replacement blades to the required height and for the maintenance engineers to be suspended in harnesses to perform functions for removal of the defective blades and installation the new blades.
Furthermore, the equipment necessary for providing the servicing, maintenance or abandonment operations may require to be lifted onto the offshore structure. The transfer of the equipment represents a risk to the structure, personnel and environment.
This problem is further exacerbated when it comes to older offshore structures, particularly oil and gas structures which due to a prolonged spell in the maritime environment can no longer support the weight of the servicing or maintenance equipment that has been traditionally lifted onto, landed and supported by the structure.